1. Technical Field
The present invention relates to: an image generating apparatus for generating image data; an image processing apparatus for processing image data concerning a document; an image reading apparatus including the image processing apparatus; an image forming apparatus including the image processing apparatus; an image generating method for generating image data; an image processing method for processing image data concerning a document; and a recording medium recording a computer program for executing processing of image data.
2. Description of Related Art
While the computerization of information advances, the widespread use of printers, copiers and multifunction printers is concurrently accelerated, and the passing of document data via a document including a sheet-like recording medium (hereinafter simply called a “document”) is also increasing more than ever.
On the other hand, two-dimensional codes are becoming more and more widespread as methods for adding additional data to printed matters. For example, as for a QR code that is one of two-dimensional codes, mobile phones possessed by many people nowadays are often provided with the functions of reading QR codes. Further, the function of creating the above-mentioned QR codes is provided as one of functions in some mobile phones, but also exists as computer software.
There have also been developed data embedding techniques in which a region where a code should be added is not required like the case of adding a QR code onto a document, the degradation in image quality is not so clearly perceived by human eyes, and additional data is embedded while taking the layout of a document into consideration. As one example of such techniques, micro gradation is disclosed in “Paper Document Security” written by Kensuke Ito and four others ([online] Fuji Xerox Technical Report, [searched on Nov. 29. 2008], Internet <URL: http://www.fujixerox.co.jp/company/tr/15/download/pdf/t—4.pdf>). The micro gradation is a technique in which a design of a document is used as a ground, and additional data is embedded in the design, thus presenting the binarized additional data with a given pattern having a density difference in the design.